Synthesis, Structural Characterization, and Growth Mechanism of Li_{1+ x}V₃O₈ Submicron Fibers for Lithium-Ion Batteries

We report on the synthesis of submicron Li_1+xV₃O₈ fibers through a facile mixed ethanol/water solution-mediated solvothermal route in the absence of surfactants. All the raw materials used are commercially available, relatively inexpensive, and low-toxic, and these can be handled in an ambient atmosphere, rendering this synthetic route as reasonably facile and efficient. To ensure a desirable and acceptable sample crystallinity and purity, we introduced a postannealing treatment at 500 °C. The monoclinic phase formation of the fiber sample was probed in detail using a series of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and selected area electron diffraction measurements. Both morphology and chemical composition could be carefully and systematically tuned in terms of generating a class of novel, pure, and well-defined motifs of Li_1+xV₃O₈. A plausible mechanism for the formation of submicron-diameter fibers has been discussed in addition to the expected phase transformation within our Li-V-O materials. Our comprehensive study should provide for needed fundamental insights into putting forth a viable synthesis strategy for the generation of well-defined morphological variants of layered oxide materials for battery applications.